A novel direction finding (DF) antenna is presented. The antenna uses interferometry with the three low-order circular phase-modes (CPMs) (-1, 0, +1) to estimate the directio-of-arrival (DOA) of a received microwave signal both in Azimuth and Elevation in the frequency range of 9-15[GHZ].
The antenna consists of two structures positioned one above the other: A bi conical dipole antenna and a novel two ports waveguide feed forming left and right hand circularly polarized (CP) fields inside a thick coax gradually being opened into a radial waveguide feeding a bi-conical horn antenna.
